Extracts from the root of plants of the genus Glycyrrhiza (Glycyrrhiza sp.), are used for flavorings, the extract imparting the flavor of licorice (liquorice), among other purposes. Current extraction methods use a hot water extraction method. This method preferentially isolates hydrophilic components of the plant root. The major single component isolated with the prior art extraction methods is glycyrrhizic acid. Glycyrrhizic acid is used predominately as a sweetener and a flavoring. Prior art extraction methods remove little or none of the hydrophobic or lipophilic components of the plant root.
Other prior art methods use organic solvents in the extraction process. These processes remove more of the lipophilic components of the plant root but have major environmental concerns connected with the use of the organic solvents. Furthermore, both of the prior art extraction processes (hot water and organic solvent) have significant problems in terms of, for example, waste generation and elimination. Organic solvent extracts have, by their very nature, the problem of spent organics to dispose of or recycle. Hot water extraction processes are preferred at extracting hydrophilic compounds are not effective in extracting lipophilic compounds. Additionally, the spent water must be treated before being put back into the water supply of the environment.
Various components of extracts of Glycyrrhiza sp. have been shown to have anti-inflammatory, antibacterial and anti-adherent effects. However, the effects seen by prior art extracts have been inconsistent. For example, in one study it was reported that incorporation of 0.25-0.5% of glycyrrhizic acid (a major component of licorice extracts made by prior art extraction methods) was ineffective in the removal or prevention of plaque build up (Goultschin, et al., J. Clin. Periodontol. 18:210-212, 1991).
Therefore, what is needed is a method for the extraction of the root of Glycyrrhiza sp. that produces less waste and causes a lesser impact on the environment than prior art extracts while at the same time producing an extract that is more effective in providing anti-inflammatory, antibacterial and anti-adherent properties by isolating a greater percentage of the total available lipophilic components of the plant root and, in particular, a greater total percentage of the available prenylated flavonoids of the plant root.